SCMatrixSubblockIter (Access access)The access variable should be one of Read, Write, Accum, and None, with the SCMatrixSubblockIter:: scope operator applied. virtual void begin ()=0Start at the beginning. virtual int ready ()=0Returns nonzero if there is another block. virtual void next ()=0Proceed to the next block. virtual SCMatrixBlock * block ()=0Return the current block. Access access () constReturn the type of Access allowed for these blocks.